The present invention relates to apparatus for monitoring and/or controlling plasma processes.
Plasma processes are used on an industrial scale in many technical fields. For example, by means of plasmas it is possible to deposit, atomize or sputter materials, e.g. in sputtering processes, to etch materials, e.g. in ionic etching and plasma etching, and to apply coatings, e.g. in plasma chemical-vapor deposition. A further special application is plasma polymerization. A considerable problem arising when performing plasma processes is their monitoring and control.
It is known to use optical emission spectroscopy for monitoring such plasma processes. The parameter monitored is the light emission of atoms or molecules in the plasma which are stimulated to produce light. It is generally not possible to obtain quantitative results in optical emission spectroscopy.